The present invention relates to a hose which is suitable for use in positions which require low gas permeability such as a fuel passage for vehicles and, more particularly, to an end structure of the hose.
In forming of a fuel passage for vehicles and other passages for volatile material, rubber has been used in many cases for a substantial material for such passages in view of formability, buffing action and economic aspects. Recently, however, there is a strong tendency that evaporation of the volatile material to the atmosphere must be strictly restricted while the volatile material flows through the hose. An attempt has been made to insert a layer of a low gas permeability material such as fluorine-contained resin (fluororesin) into a rubber layer as, for example, shown in Japanese Patent Publication (Unexamined) No. 5-44874, published Feb. 23, 1993. This attempt is the most effective if the fluororesin layer as the low gas permeability material is disposed on an inner layer of the hose since the volatile material is leaked or evaporated from the hose not only in the radial direction of the hose but also from an end portion of the hose during running longitudinally through the wall of hose. On the other hand, however, the hose having such a hard inner resin layer of a low-permeability material as described above reduces a contacting effect or sealing effect relative to mating parts when the hose is connected to the mating parts and there are cases that the volatile material diffuses from the connecting ends of the hose.
In order to prevent the leakage or evaporation of the volatile material such as a fuel out of the hose, attempts have been made to coat a sealing material or an adhesive material to the connecting position of the elements and to provide another rubber layer on an inner surface of the low permeable resin layer. The provision of a sealing material or an adhesive material to the connecting portion results in incapability of releasing the hose from the mating parts, and the additional rubber layer on the inner surface of the resin layer results in less economical because the rubber layer is disposed on the entire inner surface though it can limit the evaporation of the volatile material out of the hose.